Surprise Costume (Patreon)

The ad said that "The Sexy Strong Blacksmith's Apron will make any girl *Sexy Strong.*" She didn't realize that it would be so literal and actually transform her body, making her almost a foot (0.3m, 30cm) taller and a couple hundred pounds (90+kg) of muscle heavier. She was both pleased and saddened that the effect went away after she removed the apron after gawking at herself for a few minutes, or so she thought. She was actually slightly taller and slightly stronger after taking it off than when she put it on. And, the next day after a several hour long costume party where she was the star of the event she found that without the costume she had become several inches taller and much stronger than before she ever wore the costume.